Pole refers to the number of circuits controlled by the switch.
Double pole double throw relay symbol.
A positive and negative voltage can be placed on either end.
It has one common terminal and 2 contacts.
Sp and dp refer to single pole and double pole st and dt refer to single throw and double throw.
The polarity of the voltage does not matter.
But most frequently used relays are spdt relay and dpdt relay both are acts as electromechanical switch.
This is the diagram below to learn all the pin terminals of a double pole double throw dpdt relay.
A double pole double throw toggle switch is a combination of two individual spdt single pole double throw switches connected in the single assembly.
Sp switches control only one electrical circuit.
The main parts are all labelled and the circuit symbol is also shown the single pole double throw spdt relay is quite useful in certain applications because of its internal configuration.
The dpdt relay double pole double throw is quite interesting and can be used in various scenarious including for changing the direction of a motor as you can see in the picture below.
The 2 coil terminals is where the voltage is placed in order to energize the coil.
Single pole double throw spdt relay contains two coil terminals and common terminal then two switching terminals n o normally open n c normally close if there is not enough dc supply in.
Clicking the arrow button to reveal an internal cross section of the relay as it opens and closes.
An animation illustrating how an spdt relay works.
Look at the figure 1 2 the centre dotted line indicates that the dpdt switch is actually two spdt switches in one package.
Dp switches control two independent circuits and act like two identical switches that are mechanically linked.
Place the relay s rated coil voltage on these terminals.
Dpdt double pole double throw.